Material handling apparatus



Jan. Z, i951 R. BAcKoFEN ETAL 'Im-2,536,151

MATERIAL HANDLING APPARATUS 3 Sheets-Sheet 1 F116@ Feb. 25. 1946 Y fnifeno's: Egan aoajferz, Y @ewige Jil/mer. MM, @mt/VLM Jam; 2, 1951 R. BAcKol-'EN ErAL l 2,536,151

` MATERIAL HANDLING APPARATUS Filed Feb. 25, 1946 s sheets-shuts R. BACKOFEN r-:TAL

MATERIAL HANDLING APPARATUS Jan. 2, 19.51

3 Sheets-Sheet 3 Filed Feb. 25, 1946 /gd A Tlll u anw-- 'mm1-Alum l-latented Jan. 2, 1951 MATERIAL HANDLING APPARATUS Ryan Backofen and 'George L. Turner, Battle Creek, Mich., assignors to Clark Equipment Company, Buchanan, Mich., a corporation of Michigan Application February 25, 1946, Serial No. 649,904

7 Claims. (Ci. 214-66) l Our invention relates generally to material handling apparatus and it has particular relation to apparatus for bodily transporting one or more stacks of boxes of citrus fruit or the like..

As set forth in the copending application of Robert H. Braun, Serial No. 645,193, filed February 2, 1946, and now abandoned, it has been the practice prior thereto to manually handle and transport single stacks of boxes of citrus `iruit and the like from and to a warehouse or storage building. Because of the limitations in the manually operable apparatus of the prior art, such operations have been relatively slow and consequently have been comparatively expensive. Moreover they have been somewhat dangerous because of the likelihood of the stack being manually transported tipping or falling and injuring personnel in the vicinity.

The problem thus presented is to provide for readily and expeditiously handling one or more. preferably two or more, stacks of boxes of citrus fruit or the like at the same time. As indicated in the copendlng application of Braun above referred to various solutions to this problem are there set forth. In general they contemplate attaching auxiliary clamping and lift apparatus to a conventional fork lift truck. The arrangement is such that two or more stacks of boxes can be simultaneously clamped at the ends of the bottom boxes and at the same time the top of the stacks can be clamped with a force acting longitudinally thereof for steadying the stacks and preventing falling or tipping thereof.

The present invention constitutes an improvement over that disclosed in the Braun application. In particular it has to do with the manner in which the clamping pressure is applied to the bottom boxes of the stack or stacks for lifting the same and the application of longitudinal pressure thereto for steadying the stack or stacks during handling.

Accordingly an object of our invention, generally stated, is to provide apparatus for handling one or more stacks of boxes of citrus fruit or the like which shall be simple and eillcient in vide the clamping force that is. applied to the bottom boxes; and to employ the weight of the load compressor at the top of the stack gr stacks to steady the same.

Other objects of our invention will in part be obvious and in part appear hereafter.

Our invention is disclosed in the embodiment thereof shown in the accompanying drawings and it comprises the features of construction, combination of elements and arrangement of parts which will be exempliiled in the construction hereinafter set forth and the scope of the application of which will be indicated in the appended claims.

For a more complete understanding of the nature and scope of our invention reference may be had to the following detailed description taken in connection with the accompanying drawings in which:

Figure 1 is a view, in side elevation, of the.,

front portion of a conventional industrial truck on which is mounted material handling apparatus constructed in accordance -with our invention;

Figure 2 is a view, in front elevation, of the apparatus shown in Figure 1, the clamps being shown in their wide open positions;

Figure 3 is a view, in front elevation, of the lower portion of the apparatus shown in Figure 2, the clamps being shown in the closed or gripping positions; and

Figure 4 is a top plan view of the clamp mechanism shown in Figure 3.

Referring now particularly to Figures 1 and 2 of the drawings, it will be noted that the reference character I0 designates generally a conventional industrial truck of the fork lift type. the front wheels of which are indicated at Il. The truck I0 is provided with the conventional lift mechanism indicated generally at I4. This lift mechanism Il includes a pair of upright channel members I5 joined at their upper ends by a cross member I6. Hydraulic lift mechanism is shown generally at I1 and comprises a hydraulic cylinder I8 with which a head or yoke I9` cooperates to move relative thereto when hydraulic pressure is applied to the cylinder I8. At the opposite ends of the head or yoke I9 sprockets 2n are rotatably mounted over which lift chains 2| extend. The upper end of each of the lift chains 2| .is attached 'to a cross bar 22 extending between the channel frame uprights I5. The lower ends of the chains 2l are attached to lift mechanism in a manner which will be described hereinafter.

With a view to handling one, two. or more stacks of. boxes of citrus fruit or the like, a movable frame shown generally at 26. is carried by the frame I4. The frame 2S includes upright channel frame members 21 which are secured assaut il. From what has been said it will be understood that a relatively rigid frame It is provided by the upright members l1 andthe frame plate Il.

Nowinordertoclamptheendsofthebottom boxes of the stack or stacks. clamp members shown generally at Il and Il are provided at opposite ends of the frame plate Il. 'Ihe clamp members Il and Il comprise eveners 8| and t! having inwardly extending tines or pointed projections. and il to facilitate srippins the box ends and preventing relative slipPWe. The eveners Il and l! are pivotaliy mounted as in dicated at Il and Il on brackets I1 and Il which are integrally formed with and extend at right ansles to slid It and Il. It will be observed that the slides ll and Il are slidably mounted in guides 4I and l! which may be integrally formed with the frame plate 2l. It willnow be apparent that the clamp members Il and Il are mounted for movement toward and away from each other so as to grip or release the bottom boxes of stacks of boxes positioned therebetween. In order to move the clamp members 2l and I into clamping engagement levers 41 and 4l are pivotally mounted as indicated at II and Il on the rear side of the frame plate Il. The levers l1 and Il may be bell cranks or generally triangular shaped, as illustrated in the drawings. They maybe provided with bolts ll and I2 which extend through the slides 3l and III so as to provide mechanical connection thereto. Slots It and Il are provided in the frame plate fl to permit relative longitudinal movement of the bolts Il` and l2. Likewise slots Bl and Bl are providedin the levers l1 and I8 to permit relative movement of the bolts li and Il when the former'are rocked to and from the clamp ing positions thereof.

Now it is desirable to apply sumcient clamping force to the ends of the boxes between the clamp members I! and Il so that the boxes thereabove in the stacks can be lifted'by force applied through the bottom boxes. In accordance with our invention this clamping force is proportional to the weight of the stacks being lifted. 'I'his is accomplished by mechanically connecting the lower ends of the lift chains 2i to the levers I1 and Il as indicated at I1 and Il. Thus it will be understood that the clamp arms 2l and Il are moved toward each other into clamping engagement when the hydraulic lift mechanism i1 is operated to move the head or yoke i9 upwardly. After the clamp members 2| and 3| have moved into the clamping position, as shown more clearly in Figures 3 and 4 of the drawings, the continued upward movement of the head or yoke il lifts the frame 21 and bodily lifts the stack or stacks of boxes which are gripped by the clamp members 2l and 8l.

In order to facilitate the upward movmcnt of the frame I1 rollers Il and il are suitably mounted on the rear of the frame plate 2l and are guided in the channel upright frame members it,asshowninl'igures2and4ofthedraw ings.

In order to bias the clamp members 2l and Il to the unclamped or wide open positions springs tl and l! may be provided. Thus. when the hydraulic lift mechanism i1A is lowered, the springs Il and l! serve to bias the clampv members 2l and ll to the positions thereof, shown in Figure 2 of the drawings.

parstus of our invention contains several boxes. for example nine 'boxes as indicated by the broken outline thereof in Figure l. it is desirable that means be provided at the upper end of the frame 2s for steadying the stack or stacks during handling. For this purpose a load compresser. shown generally at Il, may be used. The load compressor Il may comprise a shelflike plate Il from which arms Il extend for slidable mounting in the channel uprights y21 of the frame'll. Transverse pins il may be provided in suitable openings 01 in the arms tl for limiting the downward movement of the load compressor Il. 0n the underside of the platelike shelf I4 there may be provided a pad Il of resilient material such as sponge rubber which serves to engage the top boxes of the stacks without marring or bruising the same.

It will be understood that the pins 6l are positioned in apertures l1 in the arms 8l in accordance with the height of the stack or stacks which are to be transported. 'Ihey are so positioned that the weight of the load compressor Il will be borne solely by the stacks of boxes clamped between the clamp members 20 and Il. In this manner a steadying action is provided for the stacks so that while they are being transported by the truck I il any tendency to fall or tip is overcome.

In operation the operator drives the truck Il toward the stack or stacks of boxes that are to be picked up and transported. Ordinarily these stacks of boxes are spaced apart a slight distance in order to permit free circulation of air or gas therebetween for preservative purposes. It is desired to maintain this spacing of the stacks while they are being transported so that it will be unnecessary to re-handle them to again provide this spacing. When the present invention is used, two or more stacks of box can be picked up readily and the spacing there- :telgleen maintained. as will be readily under- The stacks of boxes are approached with the clamp members Il and Il in the wide open position. as shown in Figure 2 of the drawings. The load compressor It is elevated te such position that it will readily clear the upper boxes of the stacks.

When the truck I0 has been moved to such position that the stacks to be transported are properly located between the clamp members 2l and 3B, the load compressor Il is released as by removing the pins It so that the pad 8l thereof rests on the upper sides of the top boxes of the stacks. 'I'he weight of the load compressor Il is thereby transmitted to the stacks in the application of force acting longitudinally thereof. The hydraulic lift mechanism i1 is then actuated. First the clamp members 2l and III are drawn inwardly against the biasing force ofthe springs Il and l2 so as to clamo the bottom boxes of the stacks therebetween. When the clamp members 29 and $0 reach the limit of their inward travel, as controlled by the dimensions of the bottom boxes, the continued operation of the lift mechanism i1 causes the stacks to be lifted on upward movement of the frame Il. The stacks need be lifted only a slight distance to clear the iioor andthen may be transported by the truck Il to the desired location.

The foregoing sequence of operations is reversed in lowering the stacks of boxes at the desired location. The truck Il may then be re- Since each stack being transported by the sp! 1I turned by repeating the operation.

v Since certain changes can be made in foregoing construction and different embodiments of the invention' can be made without departing from the spirit and scope thereof, it is intended that all matters 'shown -on the accompanying drawings or described herebefore shall be interpreted as illustrative and not in a limiting sense.

We claim as our invention: A 1

1. For combination with an industrial truck having a pair of vertically movable lift chains, a frame adapted to be mounted for vertical movement on the truck for transporting a plurality of stacks of boxes or the like, a pair of arms swingably mounted near the lower end of said frame for engaging the opposite sides of the bottom boxes of the stacks, and a pair of bell cranks pivoted on said frame and each operatively connected at 'one end to one of said arms for moving the same and at the other end to one of said lift chains, the upward movement of said lift chains causing upward movement of said frame and at the same time causing said arms to grip said bottom boxes with a force proportional to the weight of the stacks being lifted.

2. For combination with an industrial truck having a pair of vertically movable lift chains, a frame adapted to be mounted for vertical movement on the truck for` transporting a plurality of stacks of boxes or the like, a pair of arms swingably mounted near the lower end of said frame for engaging the opposite sides of the bottom bixes of the stacks, a pair of bell cranks pivoted on said frame and each connected at one end to one of said arms for moving the same and at the other end to one of said lift chains, the upward movment of said lift chains causing upward movement of said frame and at the same time causing said arms to grip said bottom boxes with a force proportional to the weight of the stacks being lifted, and a load compressor slidably mounted at the upper end of said frame for engaging the top boxes of said stacks to hold the same in place while they' are being transported by the truck.

3. For combination with an industrial truck having a pair of vertically movable lift chains, a frame adapted to be mounted for vertical movement on the truck for transporting a plurality of stacks of boxes or the like, a pair of brackets swingably mounted near the lower end of said frame, an evener pivoted intermediate its ends on the outer end of each bracket for engaging the ends of the bottom boxes of the stacks, and a pair of bell cranks pivoted on said frame and each connected at one end to one of said brackets for moving the same and at the other end to one of said lift chains, the upward movement of said lift chains causing upward movement of said frame and at the same time causing said brackets to swing toward each other thereby moving said eveners into engagement with the ends of said bottom boxes with a force proportional to the weight of the stacks being lifted.

4. For combination with an industrial truck having a vertical frame and cooperating vertically movable lift means, a lift frame arranged and adapted to be movably mounted on and guided by said vertical frame, a pair of arms extending forwardly of and movably mounted near the lower end of said lift frame for engaging the opposite sides of an object therebetween to be transported, and a pair of levers pivoted on said lift frame for movement at right angles to said arms and operatively interconnecting the same and said lift means whereby on upward movement of said lift means said lift frame is moved upwardly and said arms are moved toward said object to grip the same with a force proportional to the weight thereof for lifting the same.

5. The invention, as set forth in claim 4, wherein spring means is provided for urging said arms apart to the unclamped position.

6. The invention, as set forth in claim 4, wherein each arm includes a slide that is mounted on the lift frame for horizontal endwise movement,

va bracket integrally formed therewith and extending forwardly thereof, and an evener pivoted intermediate its ends on the outer end of said bracket.

7. The invention, as set forth in claim 6, wherein a spring reacts between the lift frame and each arm for moving the arms apart to the unclamped position. f

RYAN BACKOFEN. GEORGE L. TURNER.

' REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 974,292 Peneld Nov. 1, 1910 1,895,640 Norling Jan. 31,. 1933 1,971,952 Townsend Aug. 28, 1934 1,974,891 Poliakofi Sept. 25, 1934 2,224,913 Johnson et al Dec. 17, 1940 2,281,012 Sears Apr. 28, 1942 v 2,312,461 Woods Mar. 2, 1943 2,323,810 Fontaine July 6, 1943 2,403,356 Francis July 2, 1946 2,420,828 King May 20, 1947 FOREIGN PATENTS Number Country Date 22,561 Australia Sept. 20, 1929 

